Picotool load combined uf2 ignoring family ID

Start at the picotool load -f combined.uf2 path and the UF2 family-ID handling, then reproduce with combined files targeting RP2040 and RP2350. Done means loading selects only the firmware blocks matching the connected device instead of using only the first family ID.

According to https://github.com/microsoft/uf2#family-id , the family ID is there to allow multiple uf2 files combined into one for different targets.
(and also some comments in https://github.com/raspberrypi/picotool/pull/313 )
This works well with the RP2040 bootloader, when copying the uf2 ( cp test2.uf2 /media/arendjan/RPI-RP2/ ) then my board runs the correct firmware, either first or second part of the combined uf2.

When using picotool load -f combined.uf2, I get:

Tracking device serial number E6625C48934A7E32 for reboot
The device was asked to reboot into BOOTSEL mode so the command can be executed.

WARNING: Multiple family IDs in a single UF2 file - only using first one
WARNING: Multiple family IDs in a single UF2 file - only using first one
Loading into Flash:   [==============================]  100%

The device was asked to reboot back into application mode.

and the board either boots the code (when first part of uf2 is for it) or reconnects in bootloader mode (when correct blocks are in second part).

Using family flags ( --family rp2040 ) doesn't help.

I'd assume picotool would only upload the firmware for the connected device (or the bootloader would filter it).

(picotool build from current main)

RP2350 also not working:

UF2 correct part is second one:

Tracking device serial number DA72B1529E0666F5 for reboot
The device was asked to reboot into BOOTSEL mode so the command can be executed.

WARNING: Multiple family IDs in a single UF2 file - only using first one
Family ID 'rp2040' cannot be downloaded anywhere
ERROR: This file cannot be loaded onto a device with no partition table

UF2 correct part is first one:

WARNING: Multiple family IDs in a single UF2 file - only using first one
Family ID 'rp2350-arm-s' can be downloaded in absolute space:
  00000000->02000000
WARNING: Multiple family IDs in a single UF2 file - only using first one
Loading into Flash:   [==============================]  100%